L (Low) Class Unit
Ideal for general cleaning applications. Suitable for lower toxicity dusts such as gypsum in plasterboard.

M (Medium) Class Unit
Suitable for most construction dusts including silica dust from brick, sand, cement etc, man-made wood based dust, oak and beech woods. M class Units provide effective and reliable extraction capability. M class filter system is automatically cleaned without interruption to work time and features low air flow indicator. M Class certification means the filter within the cleaner will remove 99.9% of dust, leaving a maximum permeability of only 0.010%.

H (High) Class Unit
Suitable for dusts that have known carcinogen and health related effects (Lead, cadmium, asbestos etc). H class vacuum units use class H13 Hepa filters. Sometimes specified for works carried out in hospitals where the need for dust control is most important. H Class certification means the filter within the cleaner will remove 99.995% of dust, leaving a maximum permeability of only 0.005%.